Sir Virtualizor is VPS control panel which supports many virtualizations.
You are seeing from the point of OpenVZ only.
But OpenVZ master can manage the KVM server.
So if you want to add storage for KVM Slave you will need this Add Storage wizard.

On Launch VNC wizard if you are trying to visit on Only OpenVZ server you will get notice that for OpenVZ VNC is not available.
It is common for all Virtualizations.
Several Settings are mentioned under OpenVZ Setting so if you have any OpenVZ server as Slave you should be able to set those from other virtualization Master right ?